There has been hitherto known a liquid injection device as a device for discharging liquid as fine particles. For example, such a device is disclosed in Japanese Patent Laid-Open No. 6-40030. However, in some cases, air is compulsorily sent to a portion around a liquid injection hole, i.e., a tip of a nozzle for the purpose of evaporation or drying of injected liquid, concentration of solid components contained in the liquid, promotion of momentary movement of the injected liquid, or the like. Since a tip part of the nozzle is formed to have the same height as an outer frame of a unitarily molded device as shown in FIG. 3 in each of these devices, liquid injected along the outer frame is prone to form a thin film due to its own surface tension.
Once such a film is formed, the film acts mutually with liquid subsequently injected. Therefore, injected particles become large or small due to evaporation of the injected liquid in the periphery of the nozzle, scattering of injected particles, or an integrated action of these phenomena, and thereby injection of liquid as uniform particles is hindered. Under certain circumstances, injected liquid forming a film is dried and sticks to the periphery of a hole of the nozzle. In such a case, since a nozzle has a very small caliber by nature, dried injected liquid adheres to a tip part of the nozzle, and thereby smooth injection operation of liquid is hindered. In the worst case, the nozzle is completely clogged, and thereby there is caused a problem of incapable desired operation, for example, incapable production of a powder having an aimed particle size in the case of producing a dried powder.
Therefore, the present invention aims to provide a ceramic nozzle for a liquid injection device which is free from the problems that injection of liquid as uniform particles is hindered because of evaporation of the injected liquid in the periphery of the nozzle, scattering of injected particles, or the like, due to adhesion of liquid in the periphery of a tip part of the nozzle; injected liquid is dried and adheres to a tip part of the nozzle, and thereby smooth injection operation of liquid is hindered; or that the nozzle is completely clogged, and thereby desired operation is hindered; and the like.